Cell phone towers and hospitals, police stations, military installations and other facilities require back-up power systems, sometimes referred to as uninterruptible power supplies. These systems are used during power interruptions, such as those associated with storms and earthquakes. These back-up power supplies typically utilize arrays of lithium batteries. Lithium batteries are also used to store solar-generated power for use at night. The lithium battery arrays can include over one hundred cylinder-shaped batteries held in a single, honeycomb-shaped plastic holder with thin walls separating the battery cylinders. The length and width of the holder are specified in the IEC standard, but the depth of the holder is not regulated. The current design of the holder consists of three parts which are top, middle spacer, and bottom. Since the height of typical cylindrical lithium battery is 65 millimeters, the depth of each holder part could be around 20 millimeters. The holder with this design is easier to mold than a one-part or two-part holder, but it is more difficult to assemble, and defects such as cracks can be created during assembly. There is therefore a desire for a battery holder that improves the assembling process.
To resolve the problems at the assembling process, two-part holder designs have been considered. However, compared three-part holder designs, the draft angle of each hole must be sharper and the surface area to contact with the mold tool is larger. This leads to difficulty ejecting the molded part from the mold, and it can also increase the incidence of defects caused by molding. There therefore remains a need for molding compositions that facilitate the molding of two-part battery holders with small draft angles and large areas of contact with the mold.